Feeler lever for a hydraulic copying control



Sefit. 16; 1969. A. SCHMID 3,466,954

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5Sheets-Sheet 1 INVENTOR 4/6 e=//- slwy av Sept. 16, 1969 A. SCHMID3,466,954

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5Sheets-Sheet 2 22\ I H! i INVENTOR IAer/ Qr/nv a Sept. 16, 1969 A.SCHMID 3,

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5Sheets-Sheet 5 Fig. 5

United States Patent 3,466,954 FEELER LEVER FOR A HYDRAULIC CQPYINGCONTROL Albert Schmid, Schaifhausen, Switzerland, assignor to GeorgFischer Aktiengesellschaft, Schaffhausen, Switzerland Filed Apr. 12,1967. Ser. No. 630,295 Claims priority, application Switzerland, May 31,1966, 7,856/ 66 Int. Cl. B23b 3/28; B23q 35/04 U.S. Cl. 32-44 ClaimsABSTRACT OF THE DISCLOSURE Copying machine with a motor actuated copyingcarriage under the control of a template feeler which is mounted on theend of a pivoted arm with the arm connected to a motor control element,in which the plane containing the pivot axis of the arm and the point ofconnection of the arm to the control element is perpendicular to thefeed direction of copying carriage, and the feeler is spaced from theplane on the side opposite the tool end of the copying carriage, and thepoint of connection of the arm to the control element is closer to thepivot axis of the arm than is the feeler.

The present invention relates to a feeler lever for a hydraulic copyingcontrol for machine tools, especially copying lathes, with a workingpiston fixedly connected to the basic carriage which carries out thelongitudinal stroke and with a copying control valve member arranged onthe copying carriage for controlling the latter in conformity with atleast one templet. The copying feeler is arranged at the free end of theone-arm feeler lever which also has arranged thereon a transfer memberfor actuating the copying control valve member. The pivot axis of thefeeler lever is perpendicular to a plane defined by two intersectingstraight lines which are parallel to the feeding direction of the basiccarriage and to the transverse direction of the copying carriage. Thelongitudinal axis of the feeler lever is approximately perpendicular tothe axis of displacement of the copying carriage.

With hydraulic copying devices for copying lathes, feeler levers areemployed for the transfer of the contour to be felt on a copying templetor on a pattern to the movements of the copying control valve memberwhich controls the adjustments of the tool. Generally, the pivotalmovements of the feeler lever and thus also the displacing movements ofthe copying control are extremely small.

Heretofore known copying controls employ feeler levers the pivot axis ofwhich is parallel to the contour to be felt. With other known copyingcontrol devices, the pivot axis of the feeler lever is perpendicular tothe contour to be felt. These last mentioned designs have the advantageover the first mentioned design that contours or curves can be felt upto self-locking inclinations without the danger of jamming.

Frequently it is desired to copy contours of work pieces which withheretofore known feeler lever arrangements could not be directly feltbecause on one hand jamming was unavoidable in the journalling of thefeeler levers and on the other hand seizing at the copying templetoccurred. With such steep feeler movements a proper functioning of thehydraulic controls is no longer assured.

It is, therefore, an object of the present invention to provide a feelerlever which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a feeler lever whichwill permit the feeling of sieep curves without the danger that thelateral loads harmfully affect the feeler lever, and without the dangerthat the friction between the feeler tip and the templet exceedspermissible limits.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings, in which:

FIG. 1 diagrammatically illustrates a front view of a copying lathe.

FIG. 2 represents a side view of FIG. 1.

FIG. 3 is a partial view of FIG. 2 as seen in the direction of the arrowA.

FIG. 4 is a partial view of FIG. 3 as seen in the direction of the arrowB.

FIG. 5 represents a diagrammatic illustration of the arrangement of thefeeler lever with regard to the copying templet and of the turning toolwith regard to the work piece.

The problem underlying the present invention has been solved accordingto the present invention by an arrangement according to which the tipadapted to slide on the contour of the copying templet to be felt andpertaining to the copying feeler arranged on the feeler lever is, withregard to the longitudinal axis of the feeler lever, set back in adirection away from the turning tool, while the ratio of the distancefrom the pivot axis of the feeler lever to the feeler tip on one handand to the vertical distance between the feeler tip and the longitudinalaxis of the feeler on the other hand amounts to approximately 4.5: 1.Furthermore, the ratio of the lever arm extending from the pivot axis ofthe feeler lever to the feeler tip to the lever arm extending from thepivot axis of the feeler lever to the transfer member of the copyingcontrol member displaceable approximately parallel to the adjusting axisof the copying carriage is approximately 13:10.

Referring now to the drawing in detail, FIGS. 1 and 2 respectively showa front view and a side view of a copying turning machine with thefeeler lever according to the present invention.

A turning machine bed 3 is mounted on a stand 1 provided with aheadstock 2 and a lateral plate 5. The turning machine bed 3 is providedwith a sliding track on which a basic carriage 7 is longitudinallydisplaceable parallel to the axis of rotation 10 of a work piece. Thislongitudinal displacement may be effected by any standard means notshown. The bed 3 is furthermore provided with a track 8 on which atailstock 4 is longitudinally displaceable and is arrestable thereon byany standard means (not shown). Between the headstock 2 and thetailstock 4 theremay be clamped a work piece 9, for instance in a chuck11 adapted to be driven. The basic carriage 7 is equipped with a track12 for a copying carriage 13 which carries a turning pool 14. In anydesired manner (not shown), a piston 15 or its piston rod 16 indicatedin dotdash lines in FIG. 3 is fixedly connected to the basic carriage 7and, accordingly, the copying carriage 13 forms a working cylinder(FIGS. 3 and 4) which is displaceable on the piston 15 in the directionof the double arrow 17 along an axis 18. Depending on the copyingoperation to be carried out on the copying turning machine, the axis 18may be perpendicular to the axis of rotation 10 of the work piece or mayform another angle therewith. In the particular embodiment illustratedin the drawing, the feeding angle 30 along the axis 18 with regard tothe axis 10 of the work piece is approximately 60.

A copying templet 20 is in a maner known per se (but not illustrated)adjustable on a carrier 19 (not described in detail) above the stand 1and the lateral plate 5. Instead of a copying templet 20, also a patternmay be used.

FIGS. 3 and 4 illustrate details concerning the arrangement of thefeeler lever according to the invention. Fixedly arranged on the copyingcarriage 13 is a control valve housing 22 having a bore 24 in which acontrol column 23 by means not shown is longitudinally adjustable in adirection parallel to the direction of the working cylinder 13. Thecontrol column 23 is adapted to elfect corrections when adjusting themachine, for instance for adjusting the distance between the feeler andthe contour of the templet on one hand and between the tool and the workpiece on the other hand. Displaceably arranged in the control column 23is a copying control valve member or spool 25 which is operativelyconnected to the feeler lever 21 by means of a transfer member in theform of a bar 26.

Fixedly arranged on control column 23 is an angular clamping member 27with two bearing bolts 28, 29 forming the pivot for the feeler lever 21which is adapted to pivot about the bearing bolts 28, 29 in order tocarry out the small tilting movement necessary for the hydraulic controlof the copying carriage 13.

An imaginary longitudinal axis 31 passing through the bearing bolts 28,29 of the feeler lever 21 is approximately perpendicular to thedisplacement or feeding axis 18 of the copying carriage 13. Laterally onthe feeler lever 21 (FIG. 4) in a feeler lever arm 32 there is held afeeler 33, for instance by means of clamping screws 34. In theillustrated embodiment of the invention, the feeler tip 35 pointingtoward the side of the copying templet 20 and thereby also to the sideof the tool 14 (FIGS. 1, 2 and is set back with regard to thelongitudinal axis 31 of the feeler lever 21. The ratio of the distance43 between the pivot bolts 28, 29 of the feeler lever 21 and the feelertip 35 on one hand to the vertical distance 44 of the feeler tip 35 fromthe longitudinal axis 31 of the feeler lever 21 on the other handamounts approximately to 4.5 :1 as optimum value, for instance 130:29mm.

Arranged on the feeler lever 21 is a bar 26 forming a transfer memberfor the feeler lever movements to the copying control valve 25. Theratio of the lever arm 32 from the pivot axis 28, 29 of the feeler lever21 to the feeler tip 35 on one hand to the lever arm 32 from the pivotaxis 28, 29 to the transfer member 26 on the other hand amountsapproximately to 13:10.

FIG. 5 diagrammatically illustrates the position of the feeler lever 21with a feeler tip 35 and the contour of the copying templet 20 to befelt. Cutouts are illustrated of the contours of the non-machined workpiece 40 and the finished contour 41 of the work piece 9 rotating aboutthe work piece axis 10. The feeding angle 30 of the copying carriage 13to the axis of rotation and thus-also of the copying turning tool 14amounts to 60. The tip angle 36 of the feeler tip 35 amounts to 27.5.The copying turning tool 14 must have a tip angle of the same magnitude.In many instances it is desired at the transition area to merge thecylindrical portion of the work piece 9 with a collar 38 perpendicularthereto and thus to provide an undercut 39. This is of particularadvantage in order to be able during a grinding operation which followsthe turning operation to permit the grinding disc to run out whenlongitudinal grinding as well as when plane grinding.

As will be evident from FIG. 5, for instance on a raw work piece withthe contour of the copying templet 20 at the transition to the collar 38which originated with the preceding forging or pressing operation andcomprises considerable additional material, the frequently irregularadditional material is pre-machined by means of an additional tool 42.The contour with the undercut 39 on collar 38 can in a proper manner beproduced by means of the copying tool 14 in conformity with the copyingtemplet 20.

The operation of the hydraulic copying control as it is partially shownin FIG. 3 is known per se and disclosed for instance in German Patents846,806; 848,289; Swiss 4 Patents 234,411; 258,652; 264,699 and ItalianPatent 549,191.

The advantage of the hydraulic copying control with the feeler leveraccording to the present invention is seen primarily in that the copyingof considerably steeper contour transition portions is made possible bythe fact that the feeler tip is offset with regard to the feeler levermounting. This was not possible with heretofore known copying controls.The lateral forces acting upon the feeler lever bearing remain inadmissible limits, and also the friction inherent thereto and occurringbetween the feeler tip and the copying templet is within limits whichpermit a proper operation of the copying control.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular designs shown in the drawings but alsocomprises any modifications within the scope of the appended claims.

What is claimed is:

1. A copying machine having a frame with workpiece supporting meanstherein, a main carriage in the frame slidably guided therein formovement in the longitudinal direction of a workpiece in said workpiecesupporting means, a copying carriage on the main carriage and havingfeed movement on the main carriage in a direction transverse to theworkpiece and having tool means at the workpiece end for cutting theworkpiece, a motor connected between the main carriage and the copyingcarriage for moving the latter in feed movement transverse to theworkpiece, control means on the copying carriage for the motor, a feelerfor following a template carried by said frame, an arm having saidfeeler supported thereon at one end and having its other end pivotallysupported on said copying carriage on an axis extending perpendicular toboth the direction of movement of said main carriage and the directionof feed movement of said copying carriage, a control element connectedto said arm and to said control means to actuate the latter in responseto movement of the arm about its pivotal support, the point ofconnection of said control element to said arm being substantially inthe plane of the pivot axis of said arm which is perpendicular to thefeed direction of said copying carriage, the tip of said feeler whichengages the template accurately irrespective steepness being spacedoffset from said plane a predetermined distance on the side of saidplane opposite said cutting tool.

2. A copying machine according to claim 1, in which the point ofconnection of said control element to said arm is particularly closer tothe pivot axis of said arm than is point of connection of said feeler.

3. A copying machine according to claim 2, in which the distance fromsaid feeler to the pivot axis of said arm is about 4.5 times saidpredetermined distance of said feeler tip offset, the point ofconnection of said arm to said control element being closer to the pivotaxis of said arm than is said feeler, and the distance from the pivotaxis of said arm to said feeler being about 1.3 times the distance fromsaid pivot axis of said arm to the point of connection of said arm tosaid control element.

4. A copying machine according to claim 1, in which said feeler armextends from its pivot axis longitudinally with set back tip in theadvancing direction of movement of said main carriage.

5. A copying machine according to claim 1, in which the distance fromsaid feeler to the pivot axis of said arm is about 4.5 times saidpredetermined distance of said feeler tip offset.

References Cited UNITED STATES PATENTS GERALD A. DOST, Primary ExaminerU.S. Cl. X.R. -62

